#!/usr/bin/env python
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"""Verifies that Google Test correctly parses environment variables."""

__author__ = 'wan@google.com (Zhanyong Wan)'

import gtest_test_utils
import os
import sys
import unittest

IS_WINDOWS = os.name == 'nt'
IS_LINUX = os.name == 'posix'

COMMAND = gtest_test_utils.GetTestExecutablePath('gtest_env_var_test_')


def AssertEq(expected, actual):
  if expected != actual:
    print 'Expected: %s' % (expected,)
    print '  Actual: %s' % (actual,)
    raise AssertionError


def SetEnvVar(env_var, value):
  """Sets the env variable to 'value'; unsets it when 'value' is None."""

  if value is not None:
    os.environ[env_var] = value
  elif env_var in os.environ:
    del os.environ[env_var]


def GetFlag(command, flag):
  """Runs gtest_env_var_test_ and returns its output."""

  cmd = command
  if flag is not None:
    cmd += ' %s' % (flag,)
  stdin, stdout = os.popen2(cmd, 'b')
  stdin.close()
  line = stdout.readline()
  stdout.close()
  return line


def TestFlag(command, flag, test_val, default_val):
  """Verifies that the given flag is affected by the corresponding env var."""

  env_var = 'GTEST_' + flag.upper()
  SetEnvVar(env_var, test_val)
  AssertEq(test_val, GetFlag(command, flag))
  SetEnvVar(env_var, None)
  AssertEq(default_val, GetFlag(command, flag))


def TestEnvVarAffectsFlag(command):
  """An environment variable should affect the corresponding flag."""

  TestFlag(command, 'break_on_failure', '1', '0')
  TestFlag(command, 'color', 'yes', 'auto')
  TestFlag(command, 'filter', 'FooTest.Bar', '*')
  TestFlag(command, 'output', 'tmp/foo.xml', '')
  TestFlag(command, 'print_time', '1', '0')
  TestFlag(command, 'repeat', '999', '1')
  TestFlag(command, 'throw_on_failure', '1', '0')
  TestFlag(command, 'death_test_style', 'threadsafe', 'fast')

  if IS_WINDOWS:
    TestFlag(command, 'catch_exceptions', '1', '0')
  if IS_LINUX:
    TestFlag(command, 'stack_trace_depth', '0', '100')
    TestFlag(command, 'death_test_use_fork', '1', '0')


class GTestEnvVarTest(unittest.TestCase):
  def testEnvVarAffectsFlag(self):
    TestEnvVarAffectsFlag(COMMAND)


if __name__ == '__main__':
  gtest_test_utils.Main()